Camera

ABSTRACT

A camera includes an optical system, a housing, an image blur corrector, a displacement acquisition section, a rotary driver, a correction computer, and a drive controller. The displacement acquisition section is configured to acquire the amount of displacement of the housing. The rotary driver is configured to rotationally drive the displacement acquisition section with respect to the housing. The correction computer is configured to calculate a first correction amount at the image blur corrector from the displacement amount acquired by the displacement acquisition section. The drive controller is configured to control the operation of the rotary driver, and also controls the operation of the image blur corrector on the basis of the first correction amount.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/JP2008/003238 filed on Nov. 7, 2008. The entire disclosure ofInternational Patent Application No. PCT/JP2008/003238 is herebyincorporated herein by reference.

This application claims priority to Japanese Patent Application No.2007-292643 filed on Nov. 9, 2007. The entire disclosure of JapanesePatent Application No. 2007-292643 is hereby incorporated herein byreference.

BACKGROUND

1. Technical Field

The technology disclosed herein relates to a camera having an image blurcorrection function.

2. Description of the Related Art

A camera having an image blur correction function in order to suppressthe image degradation caused by shaking of the camera (hereinafter alsoreferred to as image blur) was known in the past. Such a camera had animage blur correction unit for driving a correcting lens, a shakedetection sensor for detecting shaking of the camera, and a correctioncontroller for controlling the operation of the image blur correctionunit according to the output of the shake detection sensor. With thiscamera, the correcting lens is driven by the image blur correction uniton the basis of the amount of shake detected by the image blur detectionsensor, so as to cancel out the image blur caused by this shaking, whichmeans that it is possible to acquire images in which image blur iscorrected.

More specifically, with a conventional camera, the X and Y axes, whichare perpendicular to the axis of incident light of the optical system,are set with respect to the camera body. This camera has a first shakedetection sensor for detecting the angular velocity (shake) of thecamera body around the X axis, and a second shake detection sensor fordetecting the angular velocity (shake) of the camera body around the Yaxis. The correction controller can detect the rotational angle of thecamera around the X and Y axes by means of the first and second shakedetection sensors. The amount by which the correcting lens is driven iscomputed by a microcomputer to correct any blurring caused by camerashake. The correcting lens is driven by a drive unit on the basis ofthis drive amount (see Patent Citation 1, for example).

To correct image blur more accurately, a camera has also been proposedin which translational shake of the camera body is detected in additionto detecting the rotational angle (shake) around the X and Y axes (seePatent Citations 2 and 3, for example). Another camera has been proposedwhich has a sensor for detecting inclination or the rotational angle(shake) around the optical axis of the camera body (see Patent Citations4 and 5). With this camera, the imaging element is driven so as tocancel out image blur caused by inclination or shake of the camera bodyaround the optical axis. Consequently, an image can be acquired in whichinclination or image blur around the optical axis has been corrected.

Patent Citation 1: Japanese Laid-Open Patent Application H3-37616

Patent Citation 2: Japanese Laid-Open Patent Application H3-46642

Patent Citation 3: Japanese Patent No. 3,513,950

Patent Citation 4: Japanese Laid-Open Patent Application H6-30327

Patent Citation 5: Japanese Patent Publication H1-53957

Patent Citation 6: Japanese Laid-Open Patent Application 2004-295027

SUMMARY

With a conventional camera, even if translational shake can be detectedby an acceleration sensor, the gravitational acceleration component thatis always acting on the camera affects the output as noise. Even if thegravitational acceleration component is eliminated ahead of time, sincethe acceleration sensor tilts with respect to the vertical directionalong with the camera, the direction of gravitational accelerationacting on the acceleration sensor is not constant. Consequently, it isdifficult to remove the gravitational acceleration component accurately,and there is a decrease in the precision of the acceleration detected bythe acceleration sensor or the amount of displacement calculated fromthis acceleration. As a result, image blur correction performance maydecrease with a conventional camera.

A camera according to a first aspect has an optical system, a housing,an image blur corrector, a displacement acquisition section, a rotarydriver, a correction computer, and a drive controller. The opticalsystem has a correcting optical system that performs image blurcorrection, and is configured to form an optical image of a subject. Theimage blur corrector is configured to correct image blur caused bymovement of the housing. The displacement acquisition section isconfigured to acquire the amount of displacement of the housing. Therotary driver is configured to rotationally drive the displacementacquisition section with respect to the housing. The correction computeris configured to calculate a first correction amount at the image blurcorrector from the displacement amount acquired by the displacementacquisition section. The drive controller is configured to control theoperation of the rotary driver, and also controls the operation of theimage blur corrector on the basis of the first correction amount.

With this camera, since the operation of the optical system driver iscontrolled by the drive controller on the basis of the first correctionamount calculated by the correction computer, the correcting opticalsystem can be driven according to the amount of movement of the camera.Consequently, image blur attributable to translational shaking of thecamera can be corrected.

Here, since the displacement acquisition section is rotationally drivenby the rotary driver, the orientation of the displacement acquisitionsection can be kept constant with respect to the vertical direction,which is the direction in which gravitational acceleration acts, forexample. Consequently, the gravitational acceleration component can beeliminated ahead of time from the displacement amount acquired by thedisplacement acquisition section, and this improves the accuracy of thedisplacement amount acquired by the displacement acquisition section.That is, image blur correction performance can be further enhanced.

Possible image blur correctors include optical types in which thecorrecting optical system is moved, sensor shift types in which theimaging element is moved, and electronic types in which an image signalis subjected to image blur correction processing. Examples of camerashere include those that are capable of only still picture imaging, thosecapable of only moving picture imaging, and those capable of both stilland moving picture imaging. Examples of cameras also include digitalstill cameras, interchangeable lens digital cameras, and digital videocameras.

A camera according to a second aspect is the camera according to thefirst aspect, wherein the displacement acquisition section overlaps therotational axis of the rotary driver when viewed along the optical axisof the imaging optical system.

A camera according to a third aspect is the camera according to thesecond aspect, wherein the detection center of the displacementacquisition section substantially coincides with the rotational axis ofthe rotary driver when viewed along the optical axis.

The “detection center” referred to here is an imaginary point that isthe center in the detection of the acceleration or displacement amountby the displacement acquisition section. If the displacement acquisitionsection is rectangular when viewed along the optical axis, the detectioncenter substantially coincides with the center of this rectangle, forexample. The phrase “the detection center of the displacementacquisition section substantially coincides with the rotational axis ofthe rotary driver when viewed along the optical axis” here encompasses acase in which the detection center completely coincides with therotational axis, as well as a case in which the detection center isoffset from the rotational axis to the extent that image blur correctionperformance is still improved.

A camera according to a fourth aspect is the camera according to thethird aspect, further comprising an imaging element configured toconvert an optical image of a subject into an image signal. The rotarydriver has a rotor to which the imaging element and the displacementacquisition section are integrally rotatably provided, and a rotationactuator configured to drive the rotor with respect to the housing. Theimaging element is disposed on the imaging optical system side of therotor. The displacement acquisition section is disposed on the oppositeside of the rotor from that of the imaging element.

A camera according to a fifth aspect is the camera according to thethird aspect, further comprising an angle acquisition section configuredto acquire the rotational angle of the housing. The correction computeris configured to calculate a second correction amount at the image blurcorrector from the rotational angle acquired by the angle acquisitionsection, using the position of the displacement acquisition section as areference. The drive controller is configured to control the operationof the image blur corrector on the basis of the first and secondcorrection amounts.

A camera according to a sixth aspect is the camera according to thethird aspect, further comprising an angle acquisition section. The angleacquisition section is configured to acquire the rotational angle of thehousing. The image blur corrector has an optical system driverconfigured to drive the correcting optical system so that the opticalpath of the imaging optical system is changed, and an imaging elementdriver configured to drive the imaging element with respect to thehousing so that the light receiving position of the optical image of thesubject is changed. The correction computer is configured to calculate asecond correction amount at the image blur corrector from the rotationalangle acquired by the angle acquisition section. The drive controller isconfigured to control the operation of the optical system driver on thebasis of the first correction amount, and is configured to control theoperation of the imaging element driver on the basis of the secondcorrection amount.

A camera according to a seventh aspect is the camera according to thethird aspect, further comprising an imaging element configured to bedriven by the rotary driver along with the displacement acquisitionsection, and configured to convert an optical image of the subject intoan image signal, and an angle acquisition section configured to acquirethe rotational angle of the housing. The drive controller is configuredto control the operation of the rotary driver so that the imagingelement is rotationally driven with respect to the housing on the basisof the rotational angle acquired by the angle acquisition section.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a front view of a camera;

FIG. 2 is a simplified diagram of the camera configuration;

FIG. 3 is a block diagram of the camera;

FIG. 4 is a diagram of the camera coordinates;

FIG. 5 is a schematic of the effect that the rotational angle θx has onthe amount of shake;

FIG. 6 is a schematic of the effect that the rotational angle θy has onthe amount of shake;

FIGS. 7A and 7B are diagrams illustrating the amount of shake Δz2 whenthe rotational center Oc coincides with the center E of a lens 102;

FIG. 8 is a diagram illustrating the amount of shake Δz1 when therotational center Oc is offset from the center E of the lens 102;

FIG. 9 is a graph of the results of calculating the pitch, yaw, and rollcomponents of the amount of shake;

FIGS. 10A to 10C are graphs of a first increase amount and the X axiscomponent Xc of the rotational center Oc;

FIGS. 11A to 11C are graphs of a first increase amount and the Y axiscomponent Yc of the rotational center Oc;

FIGS. 12A to 12C are graphs of a first increase amount and the Z axiscomponent Zc of the rotational center Oc;

FIGS. 13A to 13C are graphs of a second increase amount and thetranslational shake amount ΔX of the camera in the X axis direction;

FIGS. 14A to 14C are graphs of a second increase amount and thetranslational shake amount ΔY of the camera in the Y axis direction;

FIGS. 15A to 15C are graphs of a second increase amount and thetranslational shake amount ΔZ of the camera in the Z axis direction;

FIG. 16 is a diagram illustrating the shake amount when viewed in the Xaxis direction;

FIG. 17 is a diagram of the relation between the correction angle andthe drive amount of the correcting lens;

FIG. 18 is a graph of the relation between the correction angle and thedrive amount at various optical zoom ratios;

FIG. 19A is a diagram of when the rotational center Oc is on theopposite side from the subject, with the acceleration sensor in between,and FIG. 19B is when the rotational center Oc is between theacceleration sensor and the subject;

FIG. 20 is a diagram illustrating the shake amount when viewed in the Yaxis direction;

FIG. 21 is a diagram illustrating the shake amount when viewed in the Zaxis direction;

FIG. 22 is a diagram illustrating the shake amount when viewed in the Zaxis direction;

FIG. 23 shows the results (1) of measuring the rotational force F1 andthe centrifugal force F2;

FIG. 24 shows the results (2) of measuring the rotational force F1 andthe centrifugal force F2;

FIG. 25 shows the results (3) of measuring the rotational force F1 andthe centrifugal force F2;

FIG. 26 shows the results (4) of measuring the rotational force F1 andthe centrifugal force F2;

FIG. 27 shows the results (5) of measuring the rotational force F1 andthe centrifugal force F2;

FIG. 28 is a diagram of the total amount of shake in the Y axisdirection;

FIG. 29 is a diagram of the total amount of shake in the X axisdirection;

FIG. 30 is a simplified diagram of a camera configuration (secondembodiment);

FIG. 31 is a block diagram of the camera (second embodiment); and

FIG. 32 is a simplified diagram of the configuration of a single lensreflex camera (other embodiment).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

Embodiments will now be described through reference to the drawings.

Overall Configuration of Camera

The overall configuration of the camera 1 according to an embodimentwill now be described through reference to FIGS. 1 to 3. FIG. 1 is afront view of a camera, FIG. 2 is a diagram of the internalconfiguration of the camera 1, and FIG. 3 is a block diagram of thecamera 1.

As shown in FIGS. 1 and 2, the camera 1 has a housing 2, an opticalsystem O for forming an optical image of a subject, a lens barrel 3 forsupporting the optical system O, and an imaging element 17. The opticalsystem O is, for example, a zoom optical system having a plurality oflens groups, and has an optical axis A. With the camera 1, aperpendicular coordinate system (X, Y, and Z) is set using the opticalaxis A as a reference. The Z axis coincides with the optical axis A, andthe subject side of the camera 1 corresponds to the positive side in theZ axis direction. The lens groups of the optical system O are drivenalong the optical axis A by a zoom drive unit 13 via a plurality of lensframes included in the lens barrel 3. This allows the optical zoom ratioof the optical system O to be varied. The zoom drive unit 13 has astepping motor, for example. The operation of the zoom drive unit 13 iscontrolled by a drive controller 22 of a microcomputer 20 (discussedbelow). The drive controller 22 counts the number of control pulses sentto the zoom drive unit 13, which allows the microcomputer 20 toascertain the optical zoom ratio of the optical system O.

The camera 1 has a first angular velocity sensor 4 (an example of afirst angle acquisition section) for detecting the angular velocity ωxof the housing 2 around the X axis, a second angular velocity sensor 5(an example of an angle acquisition section) for detecting the angularvelocity ωy of the housing 2 around the Y axis, a third angular velocitysensor 6 for detecting the angular velocity oz of the housing 2 aroundthe Z axis, and a range finder 8 (an example of a distance acquisitionsection).

The first to third angular velocity sensors 4 to 6 are gyro sensors, forexample. The first to third angular velocity sensors 4 to 6 can detectthe rotary motion (angular velocity) of the housing 2. The rotationalangle can be acquired by subjecting the detected angular velocity totime integration. This computation is performed by an angle computer 24of the microcomputer 20. That is, the first to third angular velocitysensors 4 to 6 and the angle computer 24 constitute an angle acquisitionsection with which the rotational angle of the camera 1 can be acquired.

The range finder 8 is an apparatus used to measure the distance to thesubject by utilizing an infrared beam, a laser, or the like. Thedistance from the camera 1 to the subject can be measured by the rangefinder 8. More precisely, the range finder 8 can acquire the distancefrom the detection center C of an acceleration sensor 7 (discussedbelow) to the subject.

The camera 1 has an acceleration sensor 7 (an example of a displacementacquisition section) for detecting the acceleration to which the camera1 is subjected, in addition to the first to third angular velocitysensors 4 to 6. The acceleration sensor 7 is, for example, a MEMS(micro-electro-mechanical system) type of biaxial acceleration sensor,and has two perpendicular sensitivity axes (a first sensitivity axis Sxand a second sensitivity axis Sy). In a state in which a rotary driveunit 11 is in its reference position (a state in which the imagingelement 17 is not tilted with respect to the housing 2), the first andsecond sensitivity axes Sx and Sy are disposed substantially parallel tothe X axis direction and the Y axis direction. The acceleration sensor 7has a detection center C. The detection center C is an imaginary pointthat is the center in the detection of acceleration by the accelerationsensor 7, and substantially coincides with the intersection of the firstand second sensitivity axes Sx and Sy. When viewed in the Z axisdirection, the detection center C substantially coincides with theoptical axis A and the Z axis. If the acceleration sensor 7 isrectangular when viewed along the optical axis A, the detection center Csubstantially coincides with the center of this rectangle, for example.Therefore, when viewed along the optical axis A, the acceleration sensor7 overlaps the optical axis A.

When the acceleration detected by the acceleration sensor 7 hasundergone time integration twice, the amount of displacement (amount ofmovement) of the camera 1 is obtained. This computation is performed bya displacement amount computer 23 (discussed below). This displacementamount is used in the computation of the drive amount by a correctioncomputer 21. That is, the acceleration sensor 7 and the displacementamount computer 23 constitute a displacement acquisition section withwhich the amount of displacement of the camera 1 can be acquired.

The optical system O has a correcting lens 9 for correcting displacementof the optical image (hereinafter also referred to as image blur) withrespect to the imaging element 17 caused by shaking of the housing 2.The correcting lens 9 is driven in a direction perpendicular to theoptical axis A with respect to the housing 2 by a first drive unit 10and a second drive unit 12. More precisely, the first drive unit 10drives the correcting lens 9 in the Y axis direction (the pitchdirection). The second drive unit 12 drives the correcting lens 9 in theX axis direction (the yaw direction). The position of the correctinglens 9 with respect to the lens barrel 3 or the optical axis A can bedetected by a first position sensor 15 and a second position sensor 16.The first position sensor 15 detects the position of the correcting lens9 in the X axis direction. The second position sensor 16 detects theposition of the correcting lens 9 in the Y axis direction.

The camera 1 has a rotary drive unit 11 for rotationally driving theimaging element 17 around the optical axis A. The rotary drive unit 11has a rotary plate 18 that rotates around the optical axis A, and anactuator 19 that rotationally drives the rotary plate 18. The rotationalaxis K of the rotary plate 18 substantially coincides with the opticalaxis A. The actuator 19 is a stepping motor, for example, and isdirectly or indirectly fixed to the housing 2. The operation of therotary drive unit 11 is controlled by the drive controller 22. Themicrocomputer 20 can ascertain the rotational angle of the rotary plate18 with respect to the housing 2 by counting the number of controlpulses sent from the drive controller 22 to the actuator 19.

The imaging element 17 is provided on the Z axis direction positive sideof the rotary plate 18, and the acceleration sensor 7 is provided on theZ axis direction negative side (the opposite side from the imagingelement 17). Consequently, the imaging element 17 and the accelerationsensor 7 can be rotated by any angle around the optical axis A (aroundthe Z axis) with respect to the housing 2. When viewed along the opticalaxis A, the center of the imaging element 17 and the detection center Cof the acceleration sensor 7 substantially coincide with the rotationalaxis K of the rotary plate 18.

The camera 1 is controlled by the microcomputer 20. The microcomputer 20has a CPU, ROM, and RAM, and can execute various functions by readingprograms stored in the ROM into the CPU. For instance, the microcomputer20 has a function of calculating the shake amount of the camera 1, or afunction of calculating the drive amount of the correcting lens 9 fromthe rotational angle and the optical zoom ratio.

As shown in FIG. 3, the microcomputer 20 has the correction computer 21,the drive controller 22, the displacement amount computer 23, and theangle computer 24. The angle computer 24 calculates rotational anglesθx, θy, and θz by subjecting the angular velocities ωx, ωy, and ωzdetected by the first to third angular velocity sensors 4 to 6 to timeintegration. The displacement amount computer 23 calculates therespective displacement amounts by performing time integration twice onaccelerations Δx and Δy, which are first and second sensitivity axes Sxand Sy detected by the acceleration sensor 7. The correction computer 21calculates the drive amount Δd of the correcting lens 9 on the basis ofthe rotational angle and displacement amount. The drive controller 22controls the operation of the first drive unit 10, the second drive unit12, and the rotary drive unit 11 on the basis of the drive amount Δdcalculated by the correction computer 21.

As discussed above, computation is performed by the microcomputer 20based on the detection results of the various sensors, and image blurcan be corrected according to the movement of the camera 1. That is, thecorrecting lens 9, the first drive unit 10, the second drive unit 12,the imaging element 17, and the rotary drive unit 11 constitute an imageblur corrector that corrects image blur. Also, the correcting lens 9,the first drive unit 10, and the second drive unit 12 constitute a firstcorrector that uses a correction optical system to perform image blurcorrection.

Effect that Position of Rotational Center has on Shake Amount

A camera 101 will be used as an example to describe the effect that theposition of the rotational center of rotational shake of the camera hason the amount of camera shake and the amount of image blur. FIG. 4 showsthe coordinate system of the camera 101. As shown in FIG. 4, aperpendicular coordinate system (X, Y, and Z) is set using the opticalaxis A of the optical system O as a reference. The Z axis coincides withthe optical axis A.

Two kinds of shake are possible in the camera 101 during imaging:rotational shake and translational shake. Rotational shake refers toshaking of the camera 101 caused by rotation of the camera 101 around apoint present in the coordinate system. Translational shake refers toshaking of the camera 101 caused by movement of the camera 101 withrespect to the coordinate system in a state in which there is no changein the angle (orientation) of the camera 101 with respect to thecoordinate system. Usually, the shaking of the camera 1 is a combinationof these two kinds of shake.

We will let the rotational center of rotational shake of the camera 101be Oc (Xc, Yc, Zc), the rotational angle of rotational shake around theX axis be the angle θx (pitch component), the rotational angle aroundthe Y axis be the angle θy (yaw component), and the rotational anglearound the Z axis be the angle θz (roll component). We will let the Xaxis component of the translational shake V of the camera 101 be ΔX, theY axis component be ΔY, and the Z axis component be ΔZ.

(1) The Effect that the Rotational Angle θx has on the Shake Amount

FIG. 5 is a schematic of the effect that the rotational angle θx has onthe amount of shake. In FIG. 5, for the sake of convenience, the opticalsystem O is substituted with a single lens 102. We will let L be thedistance (imaging distance) from the lens 102 to a subject 103 in astate in which no shake of the camera 101 is occurring, and let f×D bethe distance from the lens 102 to the imaging element 17 in a state inwhich no shake of the camera 101 is occurring. Here, f is the focallength (such as 35 mm), and D is the optical zoom ratio.

In FIG. 5, if we assume that the lens 102 has moved to a position 102′after rotating by the angle θx around the point Oc (Xc, Yc, Zc), thenthe shake amount Δbx′ of the camera 101 when viewed in the X axisdirection is expressed by the following equation.

[Mathematical Formula 1]

Δbx′=Δx1′+Δx2′

Here, the shake amount Δx2′ is the rotational component of the shakeamount of the camera 101 when the center E of the lens 102 is used as areference, and the shake amount Δx1′ is the translational component ofthe shake amount of the camera 101 caused by offset of the center E ofthe lens 102 and the rotational center Oc. To make it easier to see thedifference between the shake amounts Δx1 and Δx2 (discussed below), Δx1′and Δx2′ are used here as the shake amounts.

When geometrically calculated, the shake amounts Δx1′, ΔL, and Δx2′ areexpressed by the following equations.

When Zc=0,

[Mathematical Formula 2]

Δx1′=Yc−Yc×cos θx

[Mathematical Formula 3]

ΔL=Yc×sin θx

When Zc≠0,

[Mathematical Formula 4]

Δx1′=√{square root over (Yc ² +Zc ²)}×sin(θx+θk)−Yc

[Mathematical Formula 5]

ΔL=Zc−√{square root over (Yc ² +Zc ²)}×cos(θx+θk)

[Mathematical Formula 6]

Δx2′=(L+ΔL)×tan θx

Furthermore, if we assume that a lens 102′ has moved to a position 102″due to translational shake V (ΔX, ΔY, ΔZ), then the translational shakeamount Δx3′ is expressed by the following equation.

[Mathematical Formula 7]

Δx3′=ΔY+ΔZ×tan θx

Because of the above, the shake amount Δbx′ is expressed by thefollowing equation.

[Mathematical Formula 8]

Δbx′=Δx1′+ΔY+(L+ΔL+ΔZ)×tan θx

(2) The Effect that the Rotational Angle θy has on the Shake Amount

FIG. 6 is a schematic of the effect that the rotational angle θy has onthe amount of shake. In FIG. 6, just as with FIG. 5, the optical systemO is substituted with a single lens 102, and we will let L be thedistance (imaging distance) from the lens 102 to the subject 103 in astate in which no shake of the camera 101 is occurring, and let f×D bethe distance from the lens 102 to the imaging element 17 in a state inwhich no shake of the camera 101 is occurring. Here, f is the focallength (such as 35 mm), and D is the optical zoom ratio.

In FIG. 6, when the camera 101 has rotated by the angle θy around therotational center Oc (Xc, Yc, Zc), and as a result the lens 102 hasmoved to the position 102′, then the shake amount Δby′ of the camera 101when viewed in the Y axis direction is expressed by the followingequation.

[Mathematical Formula 9]

Δby′=Δy1′+Δy2′

Here, the shake amount Δy2′ is the rotational component of the shakeamount of the camera 101 when the center E of the lens 102 is used as areference, and the shake amount Δy1′ is the translational component ofthe shake amount of the camera 101 caused by offset of the center E ofthe lens 102 and the rotational center Oc. To make it easier to see thedifference between the shake amounts Δy1 and Δy2 (discussed below), Δy1′and Δy2′ are used here as the shake amounts.

When geometrically calculated, the shake amounts Δy1′, ΔL, and Δy2′ areexpressed by the following equations.

When Zc=0,

[Mathematical Formula 10]

Δy1′=Xc−Xc×cos θy

[Mathematical Formula 11]

ΔL=Xc×sin θy

When Zc≠0,

[Mathematical Formula 12]

Δy1′=√{square root over (Xc ² +Zc ²)}×sin(θy+θk)−Xc

[Mathematical Formula 13]

ΔL=Zc−√{square root over (Xc ² +Zc ²)}×cos(θy+θk)

[Mathematical Formula 14]

Δy2′=(L+ΔL)×tan θy

Furthermore, if we assume that a lens 102′ has moved to a position 102″due to translational shake V (ΔX, ΔY, ΔZ) of the camera 101, then thetranslational shake amount Δy3′ is expressed by the following equation.

[Mathematical Formula 15]

Δy3′=ΔX+ΔZ×tan θy

Because of the above, the shake amount Δby′ is expressed by thefollowing equation.

[Mathematical Formula 16]

Δby′=Δy1′+ΔX+(L+ΔL+ΔZ)×tan θy

(3) Shake Amount when Viewed in the Z Axis Direction

FIGS. 7A and 7B are diagrams illustrating the amount of shake Δz2 of thecamera 101 when the rotational center Oc coincides with the center E ofthe lens 102. FIG. 8 is a diagram illustrating the amount of shake Δz′when the rotational center Oc is offset from the center E of the lens102. As shown in FIGS. 7A and 7B, when the rotational center Occoincides with the center E of the lens 102, the lens 102 rotates by theangle θz around the optical axis A. In this case, the lateral width W ofthe subject 103 is expressed by the following equation.

[Mathematical Formula 17]

W=35×L/(f×D)

Therefore, if we let Wx be the lateral width of the imaging element 17,and Wy be the longitudinal width of the imaging element 17, the shakeamount Δz2 is expressed by the following equation.

[Mathematical Formula 18]

Δz2=35/(Wx×f×D)×√{square root over (Wx ² +Wy ²)}×sin(θz/2)

In FIG. 8, if the rotational center Oc is offset from the center E, thelens 102 rotates by the angle θz around the rotational center Oc (Xc,Yc, Zc). Therefore, the shake amount Δz′ caused by offset of the centerE and the rotational center Oc is expressed by the following equation.

[Mathematical Formula 19]

Δz1=√{square root over (Xc ² Yc ²)}×tan θz

Therefore, the shake amount Δbz when viewed in the Z axis direction isexpressed by the following equation.

[Mathematical Formula 20]

Δbz=Δz1+Δz2

(4) Shake Amount Calculation Results

When it is calculated, on the basis of the above relation, who the pitchcomponent Δbx′, the yaw component Δby′, and the roll component Δbz ofthe shake amount of the camera 101 (more precisely, the pitch, yaw, androll components of the amount of displacement of an optical image withrespect to the imaging element 17 calculated on the basis of the pitchcomponent Δbx′, the yaw component Δby′, and the roll component Δbz) areaffected by the optical zoom ratio D and the imaging distance L, thefollowing results are obtained. In this calculation, it was assumed thatthe focal length f was 28 mm when the optical zoom ratio D=1, theoptical zoom ratio D was 1 to 10 times, and the imaging element 17 was aCCD with 7,200,000 pixels and a 1/2.5 format.

As discussed above, regarding the rotational shake of the camera 1, ithas been confirmed experimentally that the angles θx, θy, and θz areabout the same, and this has been discussed, for example, “3DMeasurement and Quantification of Hand Shake” published in IEICETechnical Report PRMU2006-202 (2007-1). The fact that the maximumrotational angle of rotational shake is about 0.5° has also beenconfirmed experimentally in the past. Therefore, we will assume therotational angles here to be θx=θy=θz=0.5°.

FIG. 9 is a graph of the results of calculating the pitch, yaw, and rollcomponents of the amount of shake when the rotational center Occoincides with the center E of the lens 102 and there is notranslational shake of the camera 101. That is, FIG. 9 shows the resultsof calculating when Xc=Yc=Zc 32 0. The amount of image blur referred tohere is the amount of displacement of an optical image with respect tothe imaging element 17 caused by shaking of the camera 101. The pitch,yaw, and roll components of the amount of image blur are calculated onthe basis of the above-mentioned pitch component Δbx′, yaw componentΔby′, and roll component Δbz, and are each expressed as a pixel count.It can be seen from FIG. 9 that the pitch, yaw, and roll components ofthe amount of image blur are about the same when the optical zoom ratioD is low, but as the optical zoom ratio D rises, the pitch, yaw, androll components of the amount of image blur increase.

Next, a case in which the rotational center Oc is offset from the centerE of the lens 102 will be described. FIGS. 10A to 10C are graphs of therelation between a first increase amount and the X axis component Xc ofthe rotational center Oc, FIGS. 11A to 11C are graphs of the relationbetween a first increase amount and the Y axis component Yc of therotational center Oc, and FIGS. 12A to 12C are graphs of the relationbetween a first increase amount and the Z axis component Zc of therotational center Oc. The first increase referred to here is the amountof image blur that is increased by offset of the rotational center Ocfrom the center E of the lens 102, and is the amount of image blurcorresponding to the above-mentioned shake amounts Δx1′ and Δy1′.

In the graphs, the horizontal axis is the optical zoom ratio D, and thevertical axis is the first increase amount. Also, the top graph in eachdrawing shows the imaging distance L=50 cm, the middle graph shows theimaging distance L=1 m, and the bottom graph shows the imaging distanceL=10 m. Calculations are made for three different situations, when thedistances Xc, Yc, and Zc from the rotational center Oc to the center Eof the lens 102 are (A) 0 mm, (B) 150 mm, and (C) 300 mm, respectively.The joints of the user are usually the rotational center in actualimaging. For instance, when a point that is away from the camera, suchas an elbow or a shoulder, is the rotational center, the distance fromthe center E of the lens 102 to the rotational center Oc is about 300mm.

It can be seen from FIGS. 10A to 12C that when the optical zoom ratio Dis high and the imaging distance L is short, offset between therotational center Oc and the center E of the lens 102 have a greatereffect on the amount of image blur. If we take into consideration thefact that shaking of the camera 101 results in very noticeabledegradation of the image when the actual amount of image blur is 10(pixels) or greater, offset between the rotational center Oc and thecenter E of the lens 102 can no longer be ignored above this level. Theoffset amount Xc between the rotational center Oc and the center E ofthe lens 102 in the X axis direction has a particularly great effect onthe roll component of the image blur amount, and the offset amount Ycbetween the rotational center Oc and the center E of the lens 102 in theY axis direction also greatly affects the roll component of the imageblur amount. Further, the offset amount Zc between the rotational centerOc and the center E of the lens 102 in the Z axis direction greatlyaffects both the pitch component and the yaw component of the image bluramount. In these graphs, the calculation results for the pitch componentmay look like they are not displayed, but since the calculation resultsfor the pitch component are the same as the calculation results for theyaw component, the pitch component results are merely superposed withthe yaw component results.

Effect that Translational Shake of the Camera has on Blur Amount

Next, we will describe the effect that translational shake of the camera101 has on the amount of image blur. FIGS. 13A to 13C are graphs of therelation between a second increase amount and the translational shakeamount ΔX of the camera 101 in the X axis direction, FIGS. 14A to 14Care graphs of the relation between the second increase amount and thetranslational shake amount ΔY of the camera 101 in the Y axis direction,and FIGS. 15A to 15C are graphs of the relation between the secondincrease amount and the translational shake amount ΔZ of the camera 101in the Z axis direction. In FIGS. 13A to 15C, the horizontal axis is theoptical zoom ratio D, and the vertical axis is the second increaseamount. The second increase referred to here is the amount of image blurcorresponding to translational shake, and is the amount of image blurcorresponding to the above-mentioned shake amounts Δx3′ and Δy3′.

In FIGS. 13A to 15C, the top graph in each drawing shows the imagingdistance L=50 cm, the middle graph shows the imaging distance L=1 m, andthe bottom graph shows the imaging distance L=10 m. Calculations aremade for three different situations, when the translational shakeamounts ΔX, ΔY, and ΔZ are (A) 0 mm, (B) 2 mm, and (C) 4 mm,respectively.

It can be seen from FIGS. 13A to 15C that in regard to the translationalshake amounts ΔX and ΔY, when the optical zoom ratio D is high and theimaging distance L is short, translational shake of the camera 101greatly affects the amount of image blur. More specifically, the yawcomponent of the second increase amount grows with the translationalshake amount ΔX, and the pitch component of the second increase amountgrows with the translational shake amount ΔY. The translational shakeamount ΔZ in the Z axis direction, however, hardly affects the amount ofimage blur, so the translational shake amount ΔZ may safely be ignored.

As discussed above, the position of the rotational center Oc greatlyaffects the amount of image blur, and thus cannot be ignored.Accordingly, to further improve image blur correction performance, theshake amount or image blur amount must be calculated by taking intoaccount the fact that the rotational center Oc can be in any of variouspositions.

Image Blur Correction Taking into Account Rotational Center andTranslation

As discussed above, camera shake can be divided into two types:rotational shake and translational shake. To improve the image blurcorrection effect, in regard to the rotational shake of the camera, theamount of offset between the rotational center Oc and a reference pointmust be taken into consideration.

However, finding the position of the rotational center Oc is difficultin actual practice, and the amount of camera shake cannot be calculatedby the above calculation method.

In view of this, with the camera 1, classification is performed asfollows, and computation for image blur correction is performed.

Just as with the schematic diagram shown in FIG. 4, with this camera 1 aperpendicular coordinate system (X, Y, and Z) is set in which theoptical axis A of the optical system O is the Z axis. The rotationalangles when the rotational center at which rotational shake is generatedin the camera 1 is broken down into Oc (Xc, Yc, Zc) and the rotationalshake into the perpendicular coordinate system (X, Y, Z) shall be termedθx (pitch component), θy (yaw component), and θz (roll component). Wewill let the translational shake component of the camera 1 be V=(ΔX, ΔY,ΔZ).

Here, the angle θx indicates the rotational angle of the camera 1 aroundthe X axis, and includes information related to the positive andnegative directions around the X axis. The angle θy indicates therotational angle of the camera 1 around the Y axis, and includesinformation related to the positive and negative directions around the Yaxis. The angle θz indicates the rotational angle of the camera 1 aroundthe Z axis, and includes information related to the positive andnegative directions around the Z axis. The shake amounts ΔX, ΔY, and ΔZindicate the amounts of translational shake of the camera in the X, Y,and Z axis directions, and include information related to the positiveand negative directions in the above-mentioned coordinate system.

The rotational angles θx, θy, and θz can be calculated by subjecting theangular velocities ωx, ωy, and ωz detected by the first to third angularvelocity sensors 4 to 6 to time integration.

The methods for calculating the amounts of rotational shake andtranslational shake will now be described.

Rotational Shake

(1) Amount of Shake when Viewed in the X Axis Direction

The correction of image blur caused by rotational shake with an angle ofθx (pitch component) will be described. FIG. 16 is a diagramillustrating when the rotational center of the rotational shake of thecamera 1 is Oc (Xc, Yc, Zc), and the rotational shake angle of thecamera 1 is θx (pitch component).

With the above-mentioned method for calculating the shake amount, therotational shake component Δx2′ is calculated using the center E of thelens 102 as a reference.

However, finding the position of the rotational center Oc using thecenter E of the lens 102 as a reference is difficult in actual practice,and the rotational shake component Δx2′ cannot be found.

In view of this, with this camera 1, the rotational shake component Δx2is calculated using the detection center C of the acceleration sensor 7as a reference in order to take the position of the rotational center Ocinto account in the computation. The method for calculating therotational shake component Δx2 using the detection center C of theacceleration sensor 7 as a reference will now be described.

As shown in FIG. 16, when the rotational center Oc (Xc, Yc, Zc) isrotated by the angle θx and the acceleration sensor 7 is moved to theposition 7′, the shake amount Δbx is expressed by the followingequation.

[Mathematical Formula 21]

Δbx=Δx1+Δx2

Here, the shake amount Δx2 is the rotational component of the shakeamount of the camera 1 when the detection center C of the accelerationsensor 7 is used as a reference, and the shake amount Δx1 is thetranslational component of the shake amount of the camera 1 when therotational center Oc and the detection center C of the accelerationsensor 7 are used as a reference. For the sake of convenience here, theoptical system O will be substituted with a single lens 30. The shakeamounts Δx1 and Δx2 indicate the shake amounts of the camera 1 in the Yaxis direction, and include information related to the positive andnegative directions.

Just as with the above-mentioned shake amount Δx2′, the shake amount Δx2is expressed by the following formula.

[Mathematical Formula 22]

Δx2=(L+L2+ΔL)×tan θx

In this case, the distance L2 from the lens 30 to the accelerationsensor 7 is also taken into account in addition to the distance L fromthe center E of the lens 30 to the subject 103, so the shake amount Δx2is greater than the shake amount Δx2′ by L2×tan θx (as compared to theabove-mentioned Formula 6). The distance L here can be found with therange finder 8, for example. The distance L2 is a value determined atthe design stage, and is preset in the microcomputer 20.

Also, since the shake amount Δx2 is calculating using the detectioncenter C of the acceleration sensor 7, rather than the center E of thelens 30, as a reference, the shake amount Δx1 coincides with the amountof displacement of the acceleration sensor 7 in the Y axis direction, asshown in FIG. 16. The amount of displacement of the acceleration sensor7 is obtained by subjecting the acceleration Δy in the Y axis directiondetected by the acceleration sensor 7 to time integration twice. Morespecifically, the shake amount Δx1 is expressed by the followingequation.

[Mathematical Formula 23]

Δy′=∫(∫Aydt)dt

The time t here is a predetermined unit time, such as the unit detectiontime of the acceleration sensor 7.

The shake amount Δbx that takes into account the position of therotational center Oc (more precisely, the shake amounts Δx1 and Δx2) canbe calculated by a simple method, without finding the rotational centerOc directly, by using the detection center C of the acceleration sensor7 as a reference. More specifically, an accurate shake amount Δx1 can becalculated from the acceleration Δy in the Y axis direction obtained bythe acceleration sensor 7, and an accurate rotational angle θx can befound from the angular velocity ωx around the X axis obtained by thefirst angular velocity sensor 4.

The method for correcting image blur caused by the shake amount Δb willnow be described briefly. Image blur is corrected by driving thecorrecting lens 9 in the X axis direction or Y axis direction (in thiscase, the Y axis direction) according to the various shake amounts. Therelation between the correction angle Δθ and the drive amount Δd of thecorrecting lens 9 here varies with the optical zoom ratio. The“correction angle Δθ” is the angle calculated from the imaging distanceand the shake amount Δb. In this case, as shown in FIG. 17, thecorrection angle Δθ is determined using the detection center C of theacceleration sensor 7, rather than the center E of the lens 30, as areference. The distance from the acceleration sensor 7 (more precisely,the detection center C of the acceleration sensor 7) to the subject isused for the distance to the subject in the calculation of the driveamount Δd. The relation between the correction angle Δθ and the driveamount Δd of the correcting lens 9 calculated ahead of time under thiscondition is indicated by the data in FIG. 18, for example.

In FIG. 18, horizontal axis is the drive amount Δd of the correctinglens 9, and the vertical axis is the correction angle Δθ. Since therelation between the drive amount Δd and the correction angle Δθ varieswith the optical system, it must be ascertained for each optical system.Therefore, the data shown in FIG. 18 is stored ahead of time in the ROMof the microcomputer 20, and this data can be used to find the driveamount Δd from the calculated shake amount and the optical zoom ratio.As can be seen in FIG. 18, the relation between the drive amount Δd ofthe correcting lens 9 and the correction angle Δθ varies with theoptical zoom ratio. The relation shown in FIG. 18 is the same for boththe correction angle around the X axis (pitch direction) and thecorrection angle around the Y axis (yaw direction).

Based on FIG. 17, the correction angle 0x1 corresponding to the shakeamount Δx1 is expressed by the following equation.

[Mathematical Formula 24]

Δx1=tan⁻¹(Δx1/(L+L2))

Thus, the correction angle 0x1 can be found from the shake amount Δx1,and therefore the actual drive amount Δdx1 of the correcting lens 9 canbe found. In addition to this, the drive amount Δdx2 for correcting theimage blur caused by the shake amount Δx2 can be calculated from thegraph in FIG. 18 and from the rotational angle θx corresponding to theshake amount Δx2. The drive amount Δdx obtained by summing the driveamounts Δdx1 and Δdx2 becomes the final drive amount Δdx of thecorrecting lens 9. When the correcting lens 9 is driven in the Y axisdirection by this drive amount Δdx, image blur caused by the shakeamounts Δx1 and Δx2 can be corrected.

In FIG. 16, the rotational center Oc (Xc, Yc, Zc) is to the rear of theacceleration sensor 7 (on the opposite side from the subject 103), butimage blur can be corrected by the same method as described above whenthe rotational center Oc (Xc, Yc, Zc) is in front of the accelerationsensor 7 (on the subject 103 side). This is because, as discussed above,the shake amounts Δx1 and Δx2 and the angles θx, θy, and θz includeinformation related to the positive and negative directions. Therefore,as shown in FIG. 19A, for example, the shake amount Δbx can becalculated from Formula 21 both when the rotational center Oc is on theopposite side from the subject 103 with the acceleration sensor 7 inbetween, or as shown in FIG. 19B, when the rotational center Oc isbetween the acceleration sensor 7 and the subject 103.

(2) Shake Amount when Viewed in the Y Axis Direction

Next, the correction of image blur caused by rotational shake with anangle of θy (yaw component) will be described. FIG. 20 is a diagramillustrating when the rotational center at which the rotational shake ofthe camera 1 is generated is Oc (Xc, Yc, Zc), and the rotational shakeangle of the camera 1 is θy (yaw component).

Here, just as with the angle θx discussed above, the rotational shakecomponent Δy2 is calculated using the detection center C of theacceleration sensor 7 as a reference.

In FIG. 20, if we assume that the rotational center Oc has been rotatedby the angle θy around the center, and as a result the accelerationsensor 7 moved to the position 7′, the shake amount Δby is expressed bythe following equation.

[Mathematical Formula 25]

Δby=Δy1+Δy2

Here, the shake amount Δy2 is the rotational component of the shakeamount when the detection center C of the acceleration sensor 7 is usedas a reference, and the shake amount Δy1 is the rotational component ofthe shake amount of the camera 1 caused by offset of the rotationalcenter Oc and the detection center C of the acceleration sensor 7. Theshake amounts Δy1 and Δy2 indicate shake amounts in the X axisdirection, and include information related to the positive and negativedirections.

Just as with the above-mentioned shake amount Δy2′, the shake amount Δy2is expressed by the following formula.

[Mathematical Formula 26]

Δy2=(L+L2+ΔL)×tan θy

In this case, the distance L2 from the lens 30 to the accelerationsensor 7 is also taken into account in addition to the distance L fromthe center E of the lens 30 to the subject 103, so the shake amount Δy2is greater than the shake amount Δy2′ by L2×tan θy (as compared to theabove-mentioned Formula 14).

Also, since the shake amount Δy2 is calculating using the detectioncenter C of the acceleration sensor 7, rather than the center E of thelens 30, as a reference, the shake amount Δy1 coincides with the amountof displacement of the acceleration sensor 7 in the Y axis direction, asshown in FIG. 20. The amount of displacement of the acceleration sensor7 is obtained by subjecting the acceleration Δx in the X axis directiondetected by the acceleration sensor 7 to time integration twice. Morespecifically, the shake amount Δy1 is expressed by the followingequation.

[Mathematical Formula 27]

Δy1=∫(∫Axdt)dt

As discussed above, the shake amount Δby (more specifically, the shakeamounts Δy1 and Δy2) that is affected by positional offset of therotational center can be calculated by a simple method, without findingthe rotational center Oc directly, by using the detection center C ofthe acceleration sensor 7 as a reference. More specifically, an accurateshake amount Δy1 can be calculated from the acceleration Δx in the Xaxis direction obtained by the acceleration sensor 7, and an accuraterotational angle θy can be found from the angular velocity ωy around theY axis obtained by the second angular velocity sensor 5.

Just as with the above-mentioned correction angle θx1, the correctionangle θy1 corresponding to the shake amount Δy1 obtained from theacceleration sensor 7 is expressed by the following equation.

[Mathematical Formula 28]

θy1=tan⁻¹(Δy1/(L+L2))

Just as with the above-mentioned correction angle θx1, the drive amountΔdy1 corresponding to the correction angle θy1 can be found on the basisof the graph in FIG. 18. In addition, the drive amount Δdy2 forcorrecting image blur caused by the shake amount Δy2 can be calculatedfrom the graph in FIG. 18 and from the rotational angle θy correspondingto the shake amount Δy2, as well as the above-mentioned shake amountΔx2. The drive amount My obtained by summing the drive amounts Δdy1 andΔdy2 becomes the final drive amount of the correcting lens 9. When thecorrecting lens 9 is driven in the X axis direction by this drive amountMy, image blur caused by the shake amounts Δy1 and Δy2 can be corrected.

(3) Shake Amount when Viewed in the Z Axis Direction

The correction of image blur caused by rotational shake with an angle ofθz (roll component) will be described. FIG. 21 is a diagram illustratingwhen the rotational center of the rotational shake of the camera 1 is Oc(Xc, Yc, Zc), and the rotational shake angle of the camera 1 around theZ axis is θz (roll component). The amount of shake of the camera 1caused by roll is indicated by Formula 20, and is made up of the shakeamount Δz2 when the rotational center Oc coincides with the detectioncenter C of the acceleration sensor 7, and the shake amount Δz′ causedby offset between the rotational center Oc and the detection center C ofthe acceleration sensor 7.

The shake amount Δz2 when the rotational center Oc coincides with thedetection center C of the acceleration sensor 7 corresponds to the angleθz. The angle θz can be found by subjecting the angular velocity ozaround the Z axis detected by the third angular velocity sensor 6 totime integration. The microcomputer 20 issues a command so that therotary drive unit 11 is rotated in the opposite direction by therotational angle θz on the basis of the calculated rotational angle θz.Consequently, rotational motion of the camera 1 around the Z axis isaccompanied by rotation of the imaging element 17 with respect to thehousing 2, and the shake amount Δz2 is corrected.

Next, the operation for correcting the shake amount Δz1 will bedescribed. The shake amount Δz1 can be found from the detection resultof the acceleration sensor 7. More specifically, as shown in FIG. 22,when rotational shake with a rotational angle θz (roll component)occurs, forces F1 and F2 act on the acceleration sensor 7. The force F1indicates the rotational direction component (rotational force), whilethe force F2 indicates the radial direction component (centrifugalforce).

An experiment in which the rotational force F1 and the centrifugal forceF2 were found was conducted to examine the relation between therotational force F1 and the centrifugal force F2. Theoretically, therotational force F1 and the centrifugal force F2 are expressed by thefollowing equations.

[Mathematical Formula 29]

F1/m=rα

[Mathematical Formula 30]

F2/m=rω ²

Here, m is the mass of the rotating camera, r is the rotation radius, ωis the angular velocity, and α is the angular acceleration. The angularacceleration a can be found by subjecting the output of the thirdangular velocity sensor 6 to time integration.

The measurement results found from the output of the third angularvelocity sensor 6 are shown in FIGS. 23 to 27. In FIGS. 23 to 27, theupper graph shows the value corresponding to the rotational force F1(rotation radius r x angular acceleration a in the tangentialdirection), and the lower graph shows the value corresponding to thecentrifugal force F2 (the square of the rotation radius ω×the angularvelocity ω). The formula at the bottom of each drawing indicates theratio of the maximum value of the rotational force F1 and the maximumvalue of the centrifugal force F2, that is, the value of F2/F1. FIGS. 23to 27 show the results of measuring with five test subjects.

It can be seen from the results in FIGS. 23 to 27 that since therotational angle is a relatively small value, essentially with a maximumof 0.5°, the centrifugal force F2 is quite low, being less than 1% ofthe rotational force F1, and can therefore be safely ignored. Similarly,experimental results with the first angular velocity sensor 4 and thesecond angular velocity sensor 5 are the same as the experimentalresults with the third angular velocity sensor 6, so centrifugal forcemay be ignored with no problem at all.

Because of the above, the rotational force F1 in FIG. 22 can beconsidered to be the force that is applied to the acceleration sensor 7.Since the centrifugal force F2 can thus be ignored, if the accelerationsensor 7 is disposed along the optical axis A, the force acting on theacceleration sensor 7 will be in the same direction as the displacementamount Δz1 upon rotation by the angle θz (roll component) using thepoint Oc (Xc, Yc, Zc) as the rotational center.

Here, since gravitational acceleration is also acting on theacceleration sensor 7, gravitational acceleration must also be takeninto account. In this case, the acceleration sensor 7 is rotationallydriven by the rotary drive unit 11 along with the imaging element 17with respect to the housing 2. Accordingly, there is almost no change inthe angle (orientation) of the acceleration sensor 7 with respect togravitational acceleration. Therefore, if the output value of theacceleration sensor 7 (such as the total acceleration of theaccelerations Ax and Ay) at the start of image blur correction, or fromwhen the power is switched on until the start of image blur correction,is stored in a RAM, for example, and this stored output value issubtracted from the output of the acceleration sensor 7 during imageblur correction, then the effect of the gravitational accelerationcomponent can be eliminated during image blur correction. Thiscomputation is performed by the microcomputer 20, for example.Gravitational acceleration can be considered to be the minimum value ofthe detected acceleration Ay of the acceleration sensor 7 in the Y axisdirection. The shake amount Δz1 can be calculated by subjecting theoutput of the acceleration sensor 7 to time integration twice.

Thus, with this camera 1, the shake amount Δz1 of the optical systemupon rotation by the angle θz (roll component) using the point Oc (Xc,Yc, Zc) as the rotational center can be found by a simple method, usingthe output of the acceleration sensor 7, without finding the position ofthe rotational center Oc (Xc, Yc, Zc) directly.

The value obtained by subtracting the gravitational accelerationcomponent from the X axis direction component of this shake amount Δz1(more precisely, the first sensitivity axis Sx component of the shakeamount Δz1), that is, from the detection result of the accelerationsensor 7, and then subjecting the result to time integration twice shallbe termed Δz1 x, and the value obtained by subtracting the gravitationalacceleration component from the Y axis direction component of the shakeamount Δz1 (more precisely, the second sensitivity axis Sy component ofthe shake amount Δz1), that is, from the detection result of theacceleration sensor 7, and then subjecting the result to timeintegration twice shall be termed Δz1 y. The shake amounts Δz1 x and Δz1y can be corrected by driving the correcting lens 9 in the X and Y axisdirections.

Translational Shake

Next, the correction of image blur caused by translational shake of thecamera 1 will be described. Here, as described with the results ofexamining the effect of the translation component of the camera 1 on theimage blur amount in FIGS. 13A to 15C, it can be seen that the shakeamount ΔZ of the Z axis component may be ignored with no adverse effect.Therefore, translational shake of the camera 1 may be considered to bethe translational shake amounts ΔX and ΔY.

(1) Translational Shake Amount ΔY

First, the correction operation when the camera 1 moves by thetranslational shake amount ΔY will be described. As shown in FIG. 16,when the translational shake amount ΔY occurs, the acceleration sensor 7also moves by the same distance in the Y axis direction, so thetranslational shake amount ΔY can be found from the acceleration Δy inthe Y axis direction (more precisely, the direction along the secondsensitivity axis Sy) detected by the acceleration sensor 7.

The correction angle θyh corresponding to this translational shakeamount ΔY is expressed by the following equation.

[Mathematical Formula 31]

θyh=tan⁻¹(ΔY/(L+L2))

Just as with the above-mentioned correction angle θx1, the drive amountΔdyh corresponding to the correction angle θyh can be found on the basisof the graph in FIG. 18. The image blur caused by the translationalshake amount ΔY can be corrected by moving the correcting lens 9 withthe first drive unit 10 by the drive amount Δdyh.

(2) Translational Shake Amount ΔX

Similarly, the correction operation will be described for when thetranslational shake amount ΔX occurs. As shown in FIG. 20, when thetranslational shake amount ΔX occurs, the acceleration sensor 7 alsomoves by the same distance in the X axis direction, so the translationalshake amount ΔX can be found from the acceleration Δx in the X axisdirection (more precisely, the direction along the first sensitivityaxis Sx) detected by the acceleration sensor 7.

The correction angle θxh corresponding to this translational shakeamount ΔX is expressed by the following equation.

[Mathematical Formula 32]

θxh=tan⁻¹(ΔX/(L+L2))

Just as with the above-mentioned correction angle θyh, the drive amountΔdxh corresponding to the correction angle θxh can be found on the basisof the graph in FIG. 18. The image blur caused by the translationalshake amount ΔX can be corrected by moving the correcting lens 9 withthe second drive unit 12 by the drive amount Δdxh.

As discussed above, if the detection center C of the acceleration sensor7 is disposed along the optical axis A, and the shake amount of thecamera 1 is calculated using the detection center C as a reference, thenthe calculated shake amount will be nearly unaffected by offset of thedetection center C and the rotational center Oc during the correction ofthe various components of rotation, namely, the rotational angles θx(pitch component), θy (yaw component), and θz (roll component). Thismeans that more accurate image blur correction can be achieved with thiscamera 1.

Also, image blur correction using the output of the acceleration sensor7 is possible for translational shake of the camera 1.

Total Shake Amount

The shake amounts calculated above are compiled below by component.

(1) Total Shake Amount in Y Axis Direction

FIG. 28 shows the total shake amount in the Y axis direction. In FIG.28, the shake amount Δx1 is the shake amount attributable to the factthat Yc and Zc of the rotational center Oc are not zero. The shakeamount Δx2 is the shake amount attributable to rotational shake aroundthe X axis. The shake amount Δz1 x is the shake amount attributable tothe fact that Xc and Yc of the rotational center Oc are not zero. Theshake amount ΔY is the Y axis direction component of translational shakeof the camera 1. Here, the components that utilize the output of theacceleration sensor 7 are the shake amounts Δx1, Δz1 x, and ΔY.

The correction angle θxt (an example of a first correction amount)corresponding to all the shake amounts that utilize the output of theacceleration sensor 7 is expressed by the following equation.

[Mathematical Formula 33]

θxt=tan⁻¹((Δx1+Az1x+ΔY)/(L+L2))

The drive amount Δdxt of the correcting lens 9 is calculated by thecorrection computer 21 from the relation in FIG. 18, on the basis of theoptical zoom ratio during imaging and the correction angle θxt foundfrom Formula 33. The image blur caused by the shake amounts Δx1, Δz1 x,and ΔY can be corrected by moving the correcting lens 9 with the firstdrive unit 10 by the drive amount Δdxt.

As to the shake amount Δx2, the drive amount Δdx2 of the correcting lens9 is calculated by the correction computer 21 from the relation in FIG.18, on the basis of the optical zoom ratio during imaging and therotational angle θx (an example of a second correction amount)calculated from the angular velocity ωx detected by the first angularvelocity sensor 4.

The operation of the first drive unit 10 is controlled by the drivecontroller 22 so that the drive amount Δdx, which is the sum of thedrive amounts Δdxt and Δdx2, will be calculated by the correctioncomputer 21, and the correcting lens 9 will move by the drive amountΔdx.

The image blur caused by the shake amounts Δx1, Δx2, Δz1 x, and ΔY canbe corrected by a simple method, using the detection results of thefirst angular velocity sensor 4 and the acceleration sensor 7.

A correction angle θxt that also takes into account a case in which theshake directions of the shake amounts Δx1, Δz1 x, and ΔY are differentcan be obtained by using the displacement amount calculated on the basisof the detection result of the acceleration sensor 7.

(2) Total Shake Amount in X Axis Direction

FIG. 29 shows the total shake amount in the X axis direction. In FIG.29, the shake amount Δy1 is the shake amount attributable to the factthat Xc and Zc of the rotational center Oc are not zero. The shakeamount Δy2 is the shake amount attributable to rotational shake aroundthe Y axis. The shake amount Δz1 y is the shake amount attributable tothe fact that Xc and Yc of the rotational center Oc are not zero. Theshake amount ΔX is the X axis direction component of translational shakeof the camera 1. Here, the components that utilize the output of theacceleration sensor 7 are the shake amounts Δy1, Δz1 y, and ΔX.

The correction angle θyt (an example of a first correction amount)corresponding to all the shake amounts that utilize the output of theacceleration sensor 7 is expressed by the following equation.

[Mathematical Formula 34]

θyt=tan⁻¹((Δy1+Δz1y+ΔX)/(L+L2))

The drive amount Δdyt of the correcting lens 9 is calculated by thecorrection computer 21 from the relation in FIG. 18, on the basis of theoptical zoom ratio during imaging and the correction angle θyt foundfrom Formula 34. The image blur caused by the shake amounts Δy1, Δz1 y,and ΔX can be corrected by moving the correcting lens 9 with the seconddrive unit 12 by the drive amount Δdyt.

As to the shake amount Δy2, the drive amount Δdy2 of the correcting lens9 is calculated by the correction computer 21 from the relation in FIG.18, on the basis of the optical zoom ratio during imaging and therotational angle θy (an example of a second correction amount)calculated from the angular velocity ωy detected by the second angularvelocity sensor 5.

The operation of the second drive unit 12 is controlled by the drivecontroller 22 so that the drive amount My, which is the sum of the driveamounts Δdyt and Δdy2, will be calculated by the correction computer 21,and the correcting lens 9 will move by the drive amount My.

Thus, the image blur caused by the shake amounts Δy1, Δy2, Δz1 y, and ΔXcan be corrected by a simple method, using the detection results of thesecond angular velocity sensor 5 and the acceleration sensor 7.

A correction angle θyt that also takes into account a case in which theshake directions of the shake amounts Δy1, Δz1 y, and ΔX are differentcan be obtained by using the displacement amount calculated on the basisof the detection result of the acceleration sensor 7.

(3) Total Shake Amount in Roll Direction

Regarding the total amount of shake around the Z axis, the shake amountsΔz1 x and Δz1 y caused by offset of the detection center C and therotational center Oc are corrected as shake in the X and Y axisdirections, as discussed above. Accordingly, at this point only therotational component Δz2 of the shake amount need be corrected.Specifically, the amount of rotation of the rotary drive unit 11, thatis, the angle θz, is calculated by the correction computer 21 so as tocancel out shake on the basis of the rotational angle θz calculated fromthe angular velocity oz detected by the third angular velocity sensor 6around the Z axis. The operation of the rotary drive unit 11 iscontrolled by the drive controller 22 of the microcomputer 20 so thatthe rotary plate 18 will rotate by the calculated rotational angle θz.Accordingly, the imaging element 17 rotates by the angle θz according toshake of the angle θz, and image blur caused by the shake amount Δz2 canbe corrected.

Features of Camera

Features of the Camera 1 are Discussed Below.

(1)

With the camera 1, since the shake amounts Δx2 and Δy2 are calculated bythe correction computer 21 using the position of the acceleration sensor7, and more precisely the rotational center Oc of the accelerationsensor 7, as a reference, error between the calculated shake amount andthe actual shake amount can be greatly reduced by using the position ofthe acceleration sensor 7 as a reference. For example, as shown in FIGS.18 and 19, error between the calculated shake amount and the actualshake amount can be reduced by the difference between theabove-mentioned shake amounts Δx2 and Δx2′, or the shake amounts Δy2 andΔy2′. Consequently, more accurate drive amounts Δdx and Δdy of thecorrecting lens 9 can be calculated, and image blur correctionperformance can be enhanced.

(2)

With the camera 1, since the distance L2 between the acceleration sensor7 and the optical system O is taken into account in the calculation ofthe drive amount Δd by the correction computer 21, even if the shakeamount of the camera 1 changes according to the position of therotational center Oc, error can be suppressed between the calculatedshake amount and the actual shake amount caused by the distance L2.

(3)

With the camera 1, since the acceleration sensor 7 overlaps the opticalaxis A when viewed along the optical axis A, the acceleration sensor 7is disposed near the optical axis A. More precisely, when viewed alongthe optical axis A, the detection center C of the acceleration sensor 7substantially coincides with the optical axis A. Accordingly, error inthe shake amounts Δx1, Δx2, Δy1, and Δy2 can be reduced, and moreaccurate drive amounts Δdx and Δdy can be calculated.

The phrase “the detection center C substantially coincides with theoptical axis A” here encompasses a case in which the detection center Ccompletely coincides with the optical axis A, as well as a case in whichthe detection center C is offset from the optical axis A to the extentthat image blur correction performance is still improved.

(4)

With the camera 1, since the operation of the rotary drive unit 11 iscontrolled by the drive controller 22 according to the rotational angleθz around the Z axis acquired by the third angular velocity sensor 6,the imaging element 17 can be rotationally driven according to thechange in the orientation (angle) of the camera 1. This means that imageblur attributable to rotational shake of the camera 1 around the Z axiscan be corrected.

Furthermore, since the acceleration sensor 7 can be rotationally drivenalong with the imaging element 17 by the rotary drive unit 11, theorientation of the acceleration sensor 7 can be kept constant withrespect to the vertical direction in which gravitational accelerationacts, for example. Consequently, the effect (noise) of the gravitationalacceleration component can be eliminated ahead of time from thedisplacement amount acquired by the acceleration sensor 7, and theacceleration acquired by the acceleration sensor 7, and the displacementamount calculated from the acceleration, can be increased in precision.Specifically, image blur correction performance can be enhanced withthis camera 1.

(5)

With the camera 1, the acceleration sensor 7 is disposed close to therotational axis K of the rotary drive unit 11. More precisely, whenviewed along the optical axis A, the detection center C of theacceleration sensor 7 substantially coincides with the rotational axis Kof the rotary drive unit 11. Accordingly, centrifugal force produced byrotational drive is less apt to act on the acceleration sensor 7. Thisfurther improves the precision of the displacement amount acquired bythe acceleration sensor 7.

(6)

With the camera 1, since the acceleration sensor 7 is disposed on theopposite side of the rotary plate 18 from the imaging element 17, it ispossible to achieve a configuration in which the imaging element 17 andthe acceleration sensor 7 rotate integrally, without blocking light thatis incident on the imaging element 17.

Second Embodiment

In the above embodiment, the correcting lens 9 was driven by the firstdrive unit 10 and the second drive unit 12 on the basis of the driveamount Δd of the correcting lens 9.

However, for example, the rotational components Δx2 and Δy2 ofrotational shake may be corrected by drive of the correcting lens 9, andthe shake amounts Δx1, Δy1, and Δz1 caused by remaining translation maybe corrected by moving the imaging element 17 in a directionperpendicular to the optical axis A. Specifically, the optical imageblur correction apparatus and the sensor shift type of image blurcorrection apparatus are controlled separately in this embodiment.

Those components that are substantially the same as in the aboveembodiment will be numbered the same, and will not described again.

As shown in FIGS. 30 and 31, this camera 201 has a sensor drive unit 240(an example of an imaging element driver) that drives the imagingelement 17 in two directions perpendicular to the optical axis A withrespect to the rotary plate 18 of the rotary drive unit 11. The sensordrive unit 240 drives the imaging element 17 with respect to the opticalaxis A so as to change the light receiving position of the optical imageof the subject 103. A drive controller 222 of a microcomputer 220 canalso control the operation of the sensor drive unit 240, in addition tothat of the first drive unit 10 and the second drive unit 12. Forexample, the imaging element 17 and the sensor drive unit 240 constitutea second corrector that uses an imaging element to perform image blurcorrection.

Here, for example, just as in the above embodiment, the shake amountsΔx1, Δz1 x, and ΔY are calculated by a correction computer 221 from thecorrection angle θxt (an example of a first correction amount). Thecorrection angle θyt (an example of a first correction amount) iscalculated by the correction computer 221 from the shake amounts Δy1,Δz1 y, and ΔX. Just as in the graph shown in FIG. 18, data indicatingthe relation between the correction angle θxt and the drive amount ofthe imaging element 17 is calculated ahead of time and stored in theROM, for example. The drive amount Δdx1 corresponding to the correctionangle θxt is found by the correction computer 221 on the basis of thisdata. Similarly, in the case of the correction angle θyt, a drive amountΔdy1 corresponding to the correction angle θyt is found by thecorrection computer 221. The operation of the sensor drive unit 240 iscontrolled by the drive controller 222 on the basis of the drive amountsΔdx1 and Δdy1 thus found, and the imaging element 17 moves in adirection perpendicular to the optical axis A. Consequently, image blurcaused by the shake amounts Δx1, Δz1 x, ΔY, Δy1, Δz1 y, and ΔX iscorrected.

Meanwhile, for the shake amounts Δx2 and Δy2, just as in the aboveembodiment, the drive amounts Δdx2 and Δdy2 (examples of a secondcorrection amount) corresponding to the correction angles θx and θy arecalculated by the correction computer 221. The operation of the firstdrive unit 10 and the second drive unit 12 is controlled by the drivecontroller 222 on the basis of the drive amounts Δdx2 and Δdy2.Consequently, image blur caused by the shake amounts Δx2 and Δy2, whichare the rotational components of rotational shake, can be corrected byadjustment of the optical path of the correcting lens 9.

As mentioned above, with this camera 201, the imaging element 17 isdriven by the sensor drive unit 240 on the basis of the drive amountsΔdx1 and Δdy1, and the correcting lens 9 is driven by the first driveunit 10 and the second drive unit 12 on the basis of the drive amountsΔdx2 and Δdy2. Therefore, the drive amounts of the drive units 240, 10,and 12 can be kept lower than when just the correcting lens 9 or theimaging element 17 is driven.

In addition, since image blur correction is performed by imageprocessing, degradation of the image by image blur correction can beprevented. Consequently, the movable ranges of the correcting lens 9 andthe imaging element 17 can be kept small, and more accurate image blurcorrection can be performed. Specifically, with this camera 201, goodimage blur correction performance can be maintained while the size ofthe camera is reduced.

Also, with this camera 201, it is possible to control the image blurcorrection mechanism by optical or sensor shift method, with whichsimultaneous control was difficult.

Other Embodiments

The specific constitution of the present invention is not limited to orby the above embodiments, and various modifications and changes arepossible without departing from the gist of the invention.

(1)

In the above embodiments, the correcting lens 9 was driven in the X andY axis directions, and the imaging element 17 was rotationally driven,but how the correcting lens 9 and the imaging element 17 are driven isnot limited to this. For example, a method may be employed in whichthere is no correcting lens 9, and the imaging element 17 isrotationally driven around the Z axis along with being driven in the Xand Y axis directions. In this case, the relation between the driveamount Δd of the imaging element 17 and the correction angle Δθcorresponding to this drive method may be found as in FIG. 17.

(2)

Instead of driving the correcting lens 9 in the X and Y axis directions,the lens barrel 3 may be rotationally driven with respect to the housing2.

(3)

Optical image blur correction was described in the above embodiments,but image blur may be corrected electrically by subjecting an imagesignal acquired by the imaging element 17 to special processing. In thiscase, for example, the locations where the image signals are read intoand written from the memory are controlled by an image recording unit.

(4)

In the above embodiments, a method was employed in which theacceleration sensor 7 was rotationally driven by the rotary drive unit11 along with the imaging element 17, but the acceleration sensor 7 maybe fixed with respect to the housing 2 or the lens barrel 3.

Here again, the direction of the gravitational acceleration componentmay deviate somewhat from the vertical direction, but since the maximumfor the rotational angle θz around the Z axis is about 0.5°, the effectof gravitational acceleration on the acceleration detected by theacceleration sensor 7 can be reduced, and image blur correctionperformance can be better than in the past.

In this case, it is preferable if the detection center C of theacceleration sensor 7 coincides with the optical axis A when viewedalong the optical axis A.

An advantage to this situation is that the first and second sensitivityaxes Sx and Sy of the acceleration sensor 7 to not move relative to theX and Y axes provided to the housing 2. Consequently, the direction ofacceleration detected by the acceleration sensor 7 coincides with the Xand Y axes, and the drive amount is calculated more precisely by thecorrection computer 21.

(5)

It is also conceivable that a bending optical system such as a prismwill be included in the optical system O. If so, the incident light axisfrom the subject to the prism corresponds to the above-mentioned opticalaxis A. Therefore, the acceleration sensor 7 is provided using theincident light axis as a reference.

(6)

In the above embodiments, the center of the imaging element 17, therotational axis K of the rotary drive unit 11, and the detection centerC of the acceleration sensor 7 substantially coincided with the opticalaxis A, but these may be offset from each other to the extent that theimage blur correction effect is improved.

In particular, if the acceleration sensor 7 is disposed on the rotaryplate 18 of the rotary drive unit 11, since the rotary plate 18 rotatesaccording to the movement of the housing 2 as discussed above,acceleration of substantially the same size and direction as theacceleration detected on the optical axis A can be detected.Accordingly, the acceleration sensor 7 may be provided to the rotarydrive unit 11, and there is no need for the detection center C to bedisposed on the optical axis A.

Also, since the acceleration sensor 7 and the imaging element 17 areboth provided on the rotary plate 18, there is no change in the relativepositions of the acceleration sensor 7 and the imaging element 17. Forexample, when the imaging element 17 is driven by the rotary drive unit11 according to the rotation of the camera 1 around the optical axis A,the acceleration sensor 7 is also accordingly driven rotationally withrespect to the housing 2. Therefore, the orientation of the imagingelement 17 and the acceleration sensor 7 with respect to the verticaldirection (or the horizontal direction) of the earth is kept constant.This means that the amount of displacement calculated from theaccelerations Δx and Δy detected by the acceleration sensor 7 will havesubstantially the same value as the displacement amount at therotational axis K of the rotary drive unit 11. Consequently, even if therotational center Oc is offset from the detection center C of theacceleration sensor 7, the displacement amount calculated from theacceleration detected by the acceleration sensor 7 will tend to beunaffected by the offset of the rotational center Oc.

(7)

In the above embodiments, the above-mentioned correction method wasemployed on all image blur in the pitch, yaw, and roll directions, butthe image blur correction performance of the camera 1 will be improvedif the above-mentioned method is used to correct just one component outof the pitch, yaw, and roll directions. For example, when theabove-mentioned correction method is applied to just the pitchdirection, and a conventional correction method is applied to image blurin the yaw and roll directions, the image blur correction performance ofthe camera 1 will still be improved.

In the above embodiments, the rotary drive unit 11 was used to correctimage blur in the roll direction, but the rotary drive unit 11 need notbe installed. In this case, the image blur correction performance of thecamera can be improved as long as the above-mentioned correction methodis applied to either the pitch or the yaw direction.

(8)

In the above embodiments, the output value of the acceleration sensor 7at the start of image blur correction, or from when the power isswitched on until the start of image blur correction, was used as thegravitational acceleration, but this is not the only way to determinethe gravitational acceleration. For example, the detected accelerationwhen the angular velocities detected by the first to third angularvelocity sensors 4 to 6 have dropped below a specific value may be usedas the gravitational acceleration. In this case, since the detectedacceleration in a state in which there is virtually no movement of thecamera 1 is used as the gravitational acceleration, the gravitationalacceleration components tends not to include any extra components suchas centrifugal force, and this improves the precision of thegravitational acceleration component. Consequently, the gravitationalacceleration component can be removed from the acceleration detected bythe acceleration sensor 7 during image blur correction, and thisimproves the precision of the displacement amount.

Furthermore, whether or not the camera 1 is in a horizontal state (suchas a state in which the Y axis is parallel to the vertical direction)can be decided on the basis of the image signal acquired by the imagingelement 17. It can be considered the acceleration that is detected whenthe camera 1 is in the horizontal state as the gravitationalacceleration, which increases precision of the gravitationalacceleration component. In this case, precision of the gravitationalacceleration component can be increased even though the accelerationsensor 7 is not rotated with respect to the housing 2 by the rotarydrive unit 11.

(9)

In the above embodiments, the use of an optical image blur correctionapparatus was described, but a sensor shift or electronic type of imageblur correction apparatus may be used instead. Sensor shift is a methodin which image blur correction is performed by moving the imagingelement 17 with respect to the optical axis A. An electronic methodinvolves performing image blur correction by subjecting an image signalobtained by the imaging element 17 to specific image blur correctionprocessing. With an electronic method, there is the risk of imagedeterioration by the image blur correction processing, but if the imageblur correction performance is boosted along with an increase in theprecision of the shake amount or correction angle to a greater extentthan the image deteriorates, then the overall image blur correctionperformance of the camera can be considered to have improved.

Similarly, in the second embodiment above, an example of combiningoptical and sensor shift image blur correction apparatuses wasdescribed, but one of the image blur correction apparatuses may insteadbe electronic. For example, an improvement in image blur correctionperformance can be anticipated when optical and electronic image blurcorrection apparatuses are combined. Similarly, an improvement in imageblur correction performance can be anticipated when sensor shift andelectronic image blur correction apparatuses are combined.

(10)

In the above embodiments, an example of an integrated camera wasdescribed, but the present invention can also be applied to a singlelens reflex camera composed of an interchangeable lens and a camerabody.

For example, as shown in FIG. 32, a single lens reflex camera 301 has acamera body 302 and an interchangeable lens 303 that can be mounted tothe camera body 302. An imaging element 17, a range finder 8, first tothird angular velocity sensors 4 to 6, an acceleration sensor 7, and amicrocomputer 20 are installed in the camera body 302. An optical systemO, a correcting lens 9, a first drive unit 10, a second drive unit 12,and a zoom drive unit 13 are installed in the interchangeable lens 303.

The same effect can be obtained with this single lens reflex camera 301as with the above-mentioned camera 1.

The single lens reflex camera 301 shown in FIG. 32 is just an example,and its constituent elements such as the first to third angular velocitysensors 4 to 6, the acceleration sensor 7 and the microcomputer 20 maybe provided to either the camera body 302 or the interchangeable lens303.

Also, Examples of imaging devices such as the camera 1 and the singlelens reflex camera 301 include those capable of only still pictureimaging, those capable of only moving picture imaging, and those capableof both still picture and moving picture imaging.

1. A camera, comprising: an imaging optical system configured to form anoptical image of a subject; a housing; an image blur correctorconfigured to correct image blur caused by movement of the housing; adisplacement acquisition section configured to acquire the amount ofdisplacement of the housing; a rotary driver configured to rotationallydrive the displacement acquisition section with respect to the housing;a correction computer configured to calculate a first correction amountat the image blur corrector from the displacement amount acquired by thedisplacement acquisition section; and a drive controller configured tocontrol the operation of the rotary driver, and configured to controlthe operation of the image blur corrector on the basis of the firstcorrection amount.
 2. The camera according to claim 1, wherein thedisplacement acquisition section overlaps the rotational axis of therotary driver when viewed along the optical axis of the imaging opticalsystem.
 3. The camera according to claim 2, wherein the detection centerof the displacement acquisition section substantially coincides with therotational axis of the rotary driver when viewed along the optical axis.4. The camera according to claim 3, further comprising: an imagingelement configured to convert an optical image of a subject into animage signal, wherein the rotary driver has a rotor to which the imagingelement and the displacement acquisition section are integrallyrotatably provided, and a rotation actuator configured to drive therotor with respect to the housing, the imaging element is disposed onthe imaging optical system side of the rotor, and the displacementacquisition section is disposed on the opposite side of the rotor fromthe imaging element.
 5. The camera according to claim 3, furthercomprising: an angle acquisition section configured to acquire therotational angle of the housing, wherein the correction computer isconfigured to calculate a second correction amount at the image blurcorrector from the rotational angle acquired by the angle acquisitionsection, using the position of the displacement acquisition section as areference, and the drive controller is configured to control theoperation of the image blur corrector on the basis of the first andsecond correction amounts.
 6. The camera according to claim 3, furthercomprising: an imaging element for converting an optical image of asubject into an image signal; and an angle acquisition sectionconfigured to acquire the rotational angle of the housing, wherein theimage blur corrector has an optical system driver configured to drivethe correcting optical system so that the optical path of the imagingoptical system is changed, and an imaging element driver configure todrive the imaging element with respect to the housing so that the lightreceiving position of the optical image of the subject is changed, thecorrection computer is configured to calculate a second correctionamount at the image blur corrector from the rotational angle acquired bythe angle acquisition section, and the drive controller is configured tocontrol the operation of the optical system driver on the basis of thefirst correction amount, and is configured to control the operation ofthe imaging element driver on the basis of the second correction amount.7. The camera according to claim 3, further comprising: an imagingelement configured to be driven by the rotary driver along with thedisplacement acquisition section, and configured to convert an opticalimage of the subject into an image signal; and an angle acquisitionsection configured to acquire the rotational angle of the housing,wherein the drive controller is configured to control the operation ofthe rotary driver so that the imaging element is rotationally drivenwith respect to the housing on the basis of the rotational angleacquired by the angle acquisition section.
 8. The camera according toclaim 1, further comprising: an angle acquisition section configured toacquire the rotational angle of the housing, wherein the drivecontroller is configured to control the operation of the rotary driverso that the displacement acquisition section is rotationally driven withrespect to the housing on the basis of the rotational angle acquired bythe angle acquisition section.
 9. The camera according to claim 8,further comprising: an imaging element configured to be driven by therotary driver along with the displacement acquisition section, andconfigured to convert an optical image of the subject into an imagesignal.
 10. The camera according to claim 9, wherein the rotary driverhas a rotor to which the imaging element and the displacementacquisition section are integrally rotatably provided, and a rotationactuator configured to drive the rotor with respect to the housing, theimaging element is disposed on the imaging optical system side of therotor, and the displacement acquisition section is disposed on theopposite side of the rotor from that of the imaging element.